Pilomotor Seizures Marked by Infraslow Activity and Acetazolamide Responsiveness.

A patient with pilomotor seizures post anti-LGI1 limbic encephalitis, refractory to immunotherapy and anti-epileptic drugs, was investigated with electroencephalography and magnetoencephalography. Seizures occurred daily (14.9 +/- 4.9/day), with catamenial exacerbation, inducible by hyperventilation. Anterior temporal ictal onsets were heralded (by similar to 15 sec) by high amplitude ipsilateral electromagnetic infraslow activity. The catamenial/ventilatory sensitivity and the infraslow activity (reflecting glial depolarization) suggested an ionic, CO2/pH-related glioneuronal mechanism. Furosemide decreased seizure frequency by similar to 33%. Acetazolamide led to immediate seizure freedom, but lost efficacy with daily treatment. A cycling acetazolamide regimen (2 days on, 4 days off) plus low-dose topiramate maintained >95% reduction (0.5 +/- 0.9/day) in seizures.